Process of clarifying liquids.



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Patented Nov. 5, I901.

ill/6 w H. DE RAASLOFF. PROCESS OF CLARIFYING LIQUIDS.

(Application filed Feb. 5, 1901.

(No Model.)

UNITED STATES PATENT ()EErcE.

HAROLD DE RAASLOFF, OF NEXV YORK, N. Y.

PROCESS OF CLARIFYING LIQUIDS.

SPECIFICATION forming part of Letters Patent No. 685,793, dated November 5, 1901. Application filed February 5, 1901- fierial No. 46,140. (No specimens.)

uid of the most finely divided solid matters,

producing a clear solution, which is practically free from solid particles. The result is identical with that which is usually produced by the passage of the liquid through a porous diaphragm or other filtering medium, is

much more thorough than and so different in degree as to be different in kind from the separation of suspended solid matters into layers of various degrees of fineness, and is properly and accurately designated by the term centrifugal clarification.

Essentially the process consists in causing a solution which contains the finely-divided solid matters to flow continuously through a revolving vessel and therein continuously removing the said solid matters from the liquid by centrifugal force without the aid of anyfilteringdiaphragm,cell,or medium. The solid matters removed from the liquid are continuously discharged from the vessel at a point or points relatively distant from the axis of revolution, while the clear liquid is simultaneously and continuously discharged from the vessel at a point or points relatively nearer to said axis of revolution.

The process also includes, as a subsidiary process, the holding back of the solid matters in greater or less degree when the operation is begun until they have formed a mass at the point or points of discharge of the solid matters which is sufficiently compacted to prevent the escape of the liquid from the said point or points of discharge and thereafter allowing said compacted solid matters to es cape from the vessel at the same rate as that at which they separate from the liquid, so that once the so-called plug or mass of solid matters begins to issue from the vessel it continues to discharge as long as the operation continues at practically the same degree .of consistency.

The aforesaid continuous process of centrifugal classification is of great value in various arts, and particularly in the recovery of precious metals by the cyanid processes as a substitute for the filter-beds which are now used, for, as is well known, these filter-beds are not available in the treatment of slimes, because the very fine clayey particles soon fill up the interstices of beds and stop the filtration, and even in such cases as the beds can be used in they are very slow in action as compared with my centrifugal clarification. My process will result in great saving in first cost of plant and immense increase in output in a given time.

Theprocess can be operated with varied apparatus, and in the accompanying drawings I illustrate only that which I have found preferable, not, however, limiting the process to the details of that apparatus.

Referring to the said drawings, Figure 1 is an elevation and section on the line 1 1 of Fig. 2, showing the compartment on the right with the side removed. Fig. 2 is a plan and section on the line 2 2 of Fig. l and showing the said compartment on the right with the top plate cut away. Parts of the mechanism for operating the valves are omitted from this figure. Figs. 3 and 4 are respectively a top View, the cover-plate being broken away, and a sectional elevation of one of the valves.

The parabolas shown bydotted lines in Fig.

1 indicate the theoretical shapes assumed by the surface of the liquid at two different velocities of rotation if the liquid were confined in a vessel having the shape of the outer line of the boxes and rotating at the speed thereof.

The drawings show two compartments A .B, fixed on opposite sides of a hollow shaft 0; but any number of compartments can be employed, and said compartments should be arranged symmetrically around said shaft 0. A pipe d from a suitable tank delivers the solution into the top of said shaft O, which is closed at the bottom, and said shaft 0 communicates, as at c, with said compartments A B. Said compartments A B are closed at the top by the plate E and are provided with outwardly-extending platesfg, Fig. 2, between which work the valves h 2', said valves being V of said compartment A B.

extensions of the outer walls ab, respectively, As the range of movement of the said valves 71 't'is not great, the elasticity of the metal of the walls a b is sufficient to allow for such motion, and it is not necessary to hinge said valves to said sides a b, the metal of the sides being merely bent outward to form said valves, as shown.

Said valves 77. 'i have a water-tight fit between the wallsfg and are connected by links j k with levers Z m, respectively, the inner ends of said levers being connected by pins and slots in the usual manner with a collar 0, which is worked on said shaft C by a lever 19, which is pivoted to a bracket g at r and has the usual fork or ring 5, pivotally connected with said collar 0.

Pipes '0 w for the discharge of the liquid from compartments A B, respectively, are preferably connected with the inner Walls of said compartments, near the tops thereof, as shown, and thence lead downward and outward, finally discharging into an annular trough NV. The solid matters discharge from the valves h i into the annular troughs V, and said troughs are provided with any suitable draw-off pipes, as indicated. Said pipes 02 w should be as far inward from the dischargepoints of the solid matters as possible, but outside of the parabolas which indicate the surface of the liquid, at least when no pump or similar device is used to draw 06 the filtered liquid, for if said pipes 12 w are within-1L. 6., nearer the axis of rotation than the surface assumed by the liquid when rotated, said liquid will not discharge through said pipes 'u w.

The process is operated in the following manner: \Vhen the solution first enters the vessel, the valves h t' will be closed to such a degree as to cause the solid matters which fly to the outer walls of the compartments A B as the compartments revolve to compact sufficiently in the discharge-nozzles formed by the side plates f g, the cover E, and the said valves h t to plug, as it were, said nozzles and prevent the escape of the liquid. When the plugs are formed, said valves will be opened to a degree depending on the character of the solution and the velocity of rotation and so 5 The valves are then left open the. 7 'proper degree, and thereafter the plugs issue that the plugs can escape at the same rate as they form.

continuously from their outlets at practically the same degree of consistency, while the clear liquid will be discharged continuouslyfrom pipes 0 w.

I have shown the compartments A B provided with outwardly and upwardly sloping walls a b, respectively; but the invention is not limited to any particular inclination or slope of said walls. ments in plan as contracting to the dischargenozzles, Fig. 2, and this is the preferable shape,

60 I also show said compart- 7 while the arrangement of the valves h t' as dei scribed has the advantage of avoiding shoulders, which prevent the free discharge of the solid matters when the valves are partly closed; but the process is not confined to any and discharging the filtered liquid from said I vessel at a point different from the point of discharge of the solids.

Signed at New York city this 29th day of January, 1901.

HAROLD DE RAASLOFF. W'itn esses:

WILMORE ANwAv, HENRY V. BROWN. 

